A voltage tap is needed for an energy measurement on a circuit breaker, for instance for analysing the energy consumption. Until now, an external apparatus outside the circuit breaker has been used for this purpose. In order to be able to perform the energy measurement inside the circuit breaker itself, an internal voltage tap is also needed inside the circuit breaker. US 2009/0190289 A1 discloses a circuit breaker in which a voltage tap is integrated in the circuit breaker itself so that an external module can be dispensed with. The tap for such a high voltage as applied to a primary conductor of a circuit breaker requires the use of voltage dividers to reduce the voltage to a level that is tolerated by an electronic measuring circuit. Routing the high-voltage signal via conductor tracks, wires, adapters and contacts can result in soiling, high temperatures, possible leakage paths and interference to the electronics by electrical or electromagnetic effects. Under these circumstances, it is a problem to create sufficient space in a circuit-breaker housing for the additional elements that are required, and to guarantee reliable contact is made with the primary conductor.